The reforming of petroleum hydrocarbon streams is one of the important petroleum refining processes that may be employed to provide high-octane-number hydrocarbon blending components for gasoline. In the typical reforming process, the reactions comprise dehydrogenation reactions, isomerization reactions, and hydrocracking reactions. The dehydrogenation reactions include the dehydrogenation of cyclohexanes to aromatics, the dehydroisomerization of alkylcyclopentanes to aromatics, the dehydrogenation of paraffins to olefins, and the dehydrocyclization of paraffins and olefins to aromatics. The isomerization reactions include isomerization of n-paraffins to isoparaffins, the hydroisomerization of olefins to isoparaffins, the isomerization of alkylcyclopentanes to cyclohexanes, and the isomerization of substituted aromatics. The hydrocracking reactions include hydrocracking of paraffins and hydrodesulfurization. Adequate discussion of the reactions occurring in a reforming reaction zone are presented in CATALYSIS, Vol. VI, P. H. Emmett, editor, Reinhold Publishing Corporation, 1958, pages 497-498, and PETROLEUM PROCESSING, R. J. Hengstebeck, McGraw-Hill Book Company, Inc., 1959, pages 179-184.
It is well known by those skilled in the art that several catalysts are capable of reforming petroleum naphthas and hydrocarbons that boil in the gasoline boiling range. Although reforming may be carried out through the use of molybdena-on-alumina catalysts, chromium-oxides-on-alumina catalysts, platinum-halogen-on-alumina catalysts, and platinum-aluminosilicate-material-alumina catalysts, the catalysts employing platinum as a hyrogenation component are generally employed today in the reforming processes of the petroleum industry.
It has been found that improved reforming may be effected by the use of another catalytic composition that does not contain a noble metal of Group VIII of the Periodic Table of Elements. This catalyst is particularly suited for use either as the catalyst in a reforming system that is employed to convert mildly-reformed or partially-reformed naphthas and hydrocarbon streams or as the second or last catalyst in a multiple-catalyst reforming system.
Embodiments of the reforming process employing this non-noble-metal catalyst, the process of the present invention, provide high-octane-number blending material for unleaded and/or low-lead motor fuels.